Title of Invention

PROCESS FOR THE REMOVAL OF SULFUR COMPOUNDS FORM HYDROCARBON FEEDSTOCKS

Abstract Process for the removal of contaminating sulfur compounds, more in particular thiophenic sulfur compounds, from hydrocarbon feedstocks, said process comprising contacting the feedstock in the presence of hydrogen with a sulfided nickel adsorbent, part of the nickel being present in the metallic form, of which adsorbent the rate constant for tetralin hydrogenation activity at 150°C is less than 0.01 1/s.g cat and wherein the nickel adsorbent further contains an oxide of a metal that forms stable sulfides under the conditions applied in the process for the removal of contaminating sulfur compounds from hydrocarbon feedstocks, or wherein the said hydrocarbon feedstock is subjected to a treatment with an oxide of a metal that forms stable sulfides in the process for the removal of contaminating sulfur compounds from hydrocarbon feedstocks after the said contacting with the sulfided nickel adsorbent.
Full Text Title: Process for the removal of sulfur compounds from hydrocarbon
feedstocks
The invention is directed to a process for the removal of sulfur
compounds from hydrocarbon feedstocks, more in particular to the removal of
thiophenic compounds from feedstocks comprising benzene and/or hydrocarbon
resins.
In chemical processes, such as hydrogenation and/or
dehydrogenation, often a problem presents itself in that the sulfur and/or
sulfur components in the feedstocks negatively affects the lifetime of a catalyst
used in the processes, especially in the case of nickel catalysts. To avoid this
problem, much attention has been paid to the removal of sulfur compounds
from the gaseous or liquid feedstock prior to the actual hydrogenation and/or
dehydrogenation. Further, the presence of sulfur is quite often undesirable in
view of the intended use of the hydrogenated material.
An important system for the removal of sulfur compounds from
hydrocarbon feedstocks is based on the adsorption of the sulfur compounds on
an adsorbent. Well-known adsorbents are for example a-nickel adsorbents.
These nickel adsorbents generally are in the form of supported nickel metal
crystallites.
Other systems that are known, are based on the adsorption of the
sulfur compound on an metal oxide, resulting in a reaction between the metal
oxide and the sulfur compound, producing a stable metal sulfide.
In US-A 5,482,616 a process for the removal of sulfur compound is
disclosed, wherein the sulfur compound is removed by contact with a combined
adsorbent based on a metal oxide that forms stable metal sulfides under the
reaction conditions, and a hydrogenating component, such as nickel or a
precious metal.

In US-A 5,223,470 a nickel on alumina catalyst has been described,
which has been promoted with sulfur, for the selective hydro genation of edible
oils.
In general sulfur impurities are present in feedstocks as sulfides,
mercaptans or thiophenes. However, in some feedstocks such, as certain
benzene feedstocks, middle distillates, gasoline, kerosene, MTBE and
hydrocarbon resins, the sulfur impurities are for example present as higher
thiophenes or other sulfur compounds having low reactivity (such as dimethyl-
thiosulfonate). Examples of feedstocks that contain such sulfur compounds are
feedstocks used in the production of various hydrocarbons and related
compounds, such as benzene, toluene, MTBE, furfural and related compounds,
hydrocarbon resins and the like.
Quite often, it is a requirement, that the treatment does not result
in hydrogenation of the hydrocarbon feedstock. For example, in case sulfur
compounds have to be removed from benzene, hydrogenation of the benzene
would result in a decrease of yield of the process.
US-A 6,503,388 is directed to a process for hydrogenating feedstocks
containing thiophenic impurities comprising contacting the feed with a
combination of a platinum group catalyst and a nickel catalyst, whereby the
amount of sulfur removed from the feed is considerably raised.
The capacity of a nickel adsorbent for sulfur compounds is in general
in the order of magnitude of 14 wt.%. This number is valid in case the sulfur
impurities are in the form of sulfides and/or mercaptans. However, in case the
sulfur is in the form of higher S-compounds, such as thiophenic compounds,
the capacity decreases to about 2 wt.%. As a result the amount of adsorbent
that is required increases strongly when these sulfur compounds are present
in the feedstock.
Accordingly, it is an object of the invention to provide a process for
the removal of sulfur compounds from hydrocarbon feedstocks, more in
particular to the removal of thiophenic compounds from feedstocks comprising

benzene and/or hydrocarbon resins, wherein the capacity of the adsorbent is
increased, preferably to a value comparable to that for sulfides and
mercaptans.
The present invention is based on the insight, that a nickel
adsorbent of which, the nickel surface has been deactivated, meets this object,
provided that the desulfurisation is carried out in the presence of hydrogen.
More in particular it is important, that the nickel adsorbent has a remaining
adsorption capacity for sulfur. This means that on the one hand, the adsorbent
should be sulfided in a sufficient amount to prevent hydrogenation of the
hydrocarbon, while at the same time being able to adsorb heavier sulfur
compounds, such as thiophenic sulfur compounds.
The invention is accordingly directed to a process for the removal of
contaminating sulfur compounds from hydrocarbon feedstocks, said process
comprising contacting the feedstock in the presence of hydrogen with a nickel
adsorbent, of which adsorbent the nickel surface has been deactivated with S
or an S-compound. The invention is accordingly defined as a process for the
removal of contaminating sulfur compounds, more in particular thiophenic
sulfur compounds, from hydrocarbon feedstocks, said process comprising
contacting the feedstock in the presence of hydrogen with a sulfided nickel
adsorbent, of which adsorbent the rate constant for tetralin hydrogenation
activity at 150°C is less than 0.01 1/s.g cat and wherein in said adsorbent part
of the nickel is present in the metallic form
The rate constant for tetralin hydrogenation ,one of the essential
features of the catalyst to be used in the present invention, is determined as
follows. In a micro-reactor the gas phase hydrogenation of tetralin is
performed. A hydrogen flow of 50 cm3(STP)/min having a tetralin concentration
corresponding to a saturation temperature of 13.6°C is led through a reactor at
150°C. The catalyst bed consists of 200 mg (0.1 - 2.0 cm3 of density 0.2 - 2.0
g/cm3) of catalyst in a sieve fraction of 30 - 60 mesh and diluted with inert

material in the same mesh size.(at atmospheric pressure and GHSV of 30 -
300 1/h). The reaction products are analyzed in line with a gas chromatograph.
From the analyses the tetrahn conversion is calculated.
(Conversion = (tetrahn in - tetralin out)/tetralin in).
The calculation results in a rate constant k expressed as
1/s.g(catalyst).
(k = - GHSV *(m(1-conversion))/Weight).
The activity of the material to be used in the process of the invention
should be such that the rate constant at 150 °C is less than 0.011/s.g cat. This
means in practice that almost no tetralin is hydrogenated.
This feature of the invention corresponds in general to a hydrogen
adsorption capacity of less than 10 micro-moles/g.cat. measured with static
hydrogen chemisorption at 50 C (ASTM method D 3908-82).
An other important feature of the invention resides therein that part
of the nickel is present as metal. Preferably this is at least 10 %, on atomic
basis. The upper limit of the amount of metallic nickel is determined by the
fact that no unwanted hydrogenation of the feedstock occurs. This feature is
determined in the first place by the tetralin rate constant and in a preferred
embodiment by the requirement that the nickel surface has an atomic S to Ni
ratio of at least 0.5.
It is quite surprising that the process of the invention provides a
good removal, as desulfurisation in the absence of hydrogen with merely a
nickel adsorbent does not work, and desulfurization with a regular nickel
adsorbent in the presence of hydrogen results in a run away of the reaction, as
hydrogenation of the feedstock occurs.
It is important to note that the process of the invention differs
essentially from the well-known hydro desulfurization (HDS) processes. In
these processes the sulfur containing feedstock is treated with a fully sulfided
catalyst. The sulfur containing coinpounds axe hydrogenated over the catalyst
and generally broken down to hydrogen sulfide, which is removed

subsequently. On an atomic basis, the amount of sulfur at the beginning of the
catalyst bed and at the end, after the hydrogenation treatment is the same.
Contrary thereto, the process of the present invention uses an adsorbent and
results in a decrease of the sulfur content of the feedstock.
The invention is applicable for the removal of contaminating sulfur
compounds from hydrocarbon feedstocks, more in particular those feedstocks
described hereinabove.
The invention can even be used for the treatment of feedstocks that
contain unsaturation, which should not be hydrogenated. It has been found
that the process of the invention results in efficient removal of the
contaminating sulfur compounds, without hydrogenation of the feedstock.
However, in some instances, the condition may be adapted to obtain
stabilisation of a feedstock, such as removal of gum precursors (styrene type
compounds),which requires hvydrogenation of some unsaturated components.
In a preferred embodiment of the invention the adsorbent is used in
combination with a metal oxide adsorbent. The metal of the adsorbent is a
metal that forms stable sulfides under the conditions applied in the process for
the removal of contaminating sulfur compounds from hydrocarbon feedstocks.
This metal oxide can either be used in the nickel adsorbent, such as described
in U8-A 5,482,616, although the adsorbent does not necessarily has to meet all
the criteria of said invention. For example, it is possible to use simple physical
mixtures, not meeting the requirements of the particle size thereof.
In another embodiment it is possible to treat the effluent of the
treatment with the nickel adsorbent, with the said metal oxide, preferably in a
bed thereof.
In both embodiments, the effect is a further improved and more
reliable sulfur removal.
The removal of the contaminating sulfur compounds is preferably
done at a hydrogen partial pressure is between 0.1 and 200 bar and preferably
between 10 and 75 bar and more in particular between 30 and 50 bar. The

temperature is preferably between 50 and 300 °C, preferably between 100 and
200 °C.
The process is preferably carried out with an LHSV between 0.1 and
10 hr-l, whereas the GHSV preferably lies between 50 and 5000 hr-1.
The adsorbent may be prepared by a process wherein a passivated
nickel adsorloent material containing oxidic nickel, optionally on a support or
in the presence of a structural promoter, is reduced with hydrogen at a
temperature between 100 and 200°C, followed by treatment of the surface of
the reduced material with sulfur or a sulfur compound, preferably in an inert
solvent, to yield the nickel adsorbent as defined hereinabove. In case a nickel
adsorbent is prepared directly from a nickel oxide precursor, without prior
reduction and passivation, as above, the temperature of reduction is preferably
between 100 and 500°C.
The sulfur compounds to be used are preferably aromatic sulfur
compounds, such as di-benzo-thiophene, 2-methyl thiophene, benzothiophene
or dimethyl thiophene. It is also possible to use sulfur powder, polysulfide and
the like. The treatment encompasses preferably precipitating S, a polysulfide
or an S-compound on the nickel adsorbent, or impregnating the nickel
adsorbent with S, a polysulfide or an S-compound sulfur compound. Co-
precipitation of the catalyst including the sulphur as described in US-A
5,223,470 is also a possibility. An advantage of this latter process is the
improved activity of the final nickel adsorbent. This process includes a step of
coprecipitating a precursor for the adsorbent from a solution containing nickel,
optionally a dissolved or solid support or structural promoter precursor
material and a sulfur compound, and calcining and/or passivating the
precipitated material.


Example 1
A 60 wt.% nickel on silica adsorbent was prepared by co-
preeipitation. Sulphur was added in the precipitation step as a sulphide salt.
The precipitate was washed with de-ionized water and filtered. The filter-cake
was dried and calcined. The calcined material was extruded into 1/16" trilobes.
The extrudates were dried, calcined and reduced/stabilized.
The product is adsorbent B and contained 60 wt.% Ni and 2.75 wt.%
Sulphur. Adsorbent B was evaluated in the tetrahn activity test after
reduction in hydrogen at 425°C for 2 hours and had a rate constant of 0.0085
l/s.g(cat.) at 150°C. The amount of metallic nickel in the adsorbent was 30 %,
calculated on the total amount of nickel.
Example 2
A 60 wt.% nickel extrudate (reduced and passivated) was applied as
the base adsorbent. This material was loaded in a reactor and treated with a
paraffmic solvent containing 100 ppm Sulphur as di-benzo-thiophene. The
adsorbent was treated at 150°C and 30 bar hydrogen pressure. At LHSV 10
1/hr; GHSV 1500 1/hr the treatment was monitored measuring the DBT
content in the effluent. Once the effluent sulphur content and the feed sulphur
content were constant the treatment was considered as finished. Next the
adsorbent was dried. The adsorbent obtained is adsorbent A
Adsorbent A was loaded in a fixed bed reactor and applied in the
desulphurization of benzene. The feed contained 4.0 wt-ppm S as thiophene.
The conditions were as follows: LHSV 2 1/hr; GHSV 500 1/hr.
The results at 170°C were as follows:
Pressure 10 bar
92.5 % removal or 308 ppb S in the product

Pressure 20 bar
98.5 % removal or 59 ppb S in the product
Pressure 40 bar
99.6 % removal or 28 ppb S in the product
Under the above conditions no benzene hydrogenation activity was observed.
Example 3
Adsorbent A was loaded in a fixed bed reactor and applied in the
desulphurization of benzene that contained additionally 1000 wt-ppm Styrene.
Styrene is a typical component in crude benzene and causes often fouling
problems, due to polymer formation on the catalyst surface. The feed contained
4.0 wt-ppm S as thiophene.
The conditions were as follows: LHSV 2 1/hr; GHSV 500 1/hr
The results at 150 °C and 40 bar pressure are as follows:
Benzene conversion 0 %
Styrene conversion 100 %
Thiophene conv. 99.0 %

WE CLAIM:
1. Process for the removal of contaminating sulfur compounds, more in
particular thiophenic sulfur compounds, from hydrocarbon feedstocks, said
process comprising contacting the feedstock in the presence of hydrogen
with a sulfided nickel adsorbent, part of the nickel being present in the
metallic form, of which adsorbent the rate constant for tetralin
hydrogenation activity at 150°C is less than 0.01 1/s.g cat and wherein
a. the nickel adsorbent further contains an oxide of a metal that forms
stable sulfides under the conditions applied in the process for the
removal of contaminating sulfur compounds from hydrocarbon
feedstocks, or
b. wherein the said hydrocarbon feedstock is subjected to a treatment
with an oxide of a metal that forms stable sulfides in the process for
the removal of contaminating sulfur compounds from hydrocarbon
feedstocks after the said contacting with the sulfided nickel
adsorbent.
2. Process as claimed in claim 1, wherein at least 10% on atomic basis, of
the nickel is in the metallic form.

3. Process as claimed in claim 1 or 2, wherein the nickel surface has an
atomic S to Ni ratio of at least 0.5.
4. Process as claimed in any one of the claims 1-3, wherein the nickel
adsorbent further contains an oxide of a metal that forms stable sulfides
under the conditions applied in the process for the removal of
contaminating sulfur compounds from hydrocarbon feedstocks.
5. Process as claimed in claims 1-4, wherein the said hydrocarbon feedstock
is subsequently subjected to a treatment with an oxide of a metal that
forms stable sulfides in the process for the removal of contaminating sulfur
compounds from hydrocarbon feedstocks.


Process for the removal of contaminating sulfur compounds, more in particular
thiophenic sulfur compounds, from hydrocarbon feedstocks, said process
comprising contacting the feedstock in the presence of hydrogen with a sulfided
nickel adsorbent, part of the nickel being present in the metallic form, of which
adsorbent the rate constant for tetralin hydrogenation activity at 150°C is less
than 0.01 1/s.g cat and wherein the nickel adsorbent further contains an oxide of
a metal that forms stable sulfides under the conditions applied in the process for
the removal of contaminating sulfur compounds from hydrocarbon feedstocks, or
wherein the said hydrocarbon feedstock is subjected to a treatment with an oxide
of a metal that forms stable sulfides in the process for the removal of
contaminating sulfur compounds from hydrocarbon feedstocks after the said
contacting with the sulfided nickel adsorbent.

Documents:

00661-kolnp-2006-abstract.pdf

00661-kolnp-2006-claims.pdf

00661-kolnp-2006-description complete.pdf

00661-kolnp-2006-form 1.pdf

00661-kolnp-2006-form 2.pdf

00661-kolnp-2006-form 3.pdf

00661-kolnp-2006-form 5.pdf

00661-kolnp-2006-gpa.pdf

00661-kolnp-2006-international publication.pdf

00661-kolnp-2006-pct request.pdf

00661-kolnp-2006-priority document.pdf

661-KOLNP-2006-CORRESPONDENCE 1.1.pdf

661-kolnp-2006-correspondence.pdf

661-kolnp-2006-examination report.pdf

661-kolnp-2006-form 18.pdf

661-kolnp-2006-form 3.pdf

661-kolnp-2006-form 5.pdf

661-KOLNP-2006-FORM-27.pdf

661-kolnp-2006-gpa.pdf

661-kolnp-2006-granted-abstract.pdf

661-kolnp-2006-granted-claims.pdf

661-kolnp-2006-granted-description (complete).pdf

661-kolnp-2006-granted-form 1.pdf

661-kolnp-2006-granted-form 2.pdf

661-kolnp-2006-granted-specification.pdf

661-KOLNP-2006-OTHERS.pdf

661-kolnp-2006-others1.1.pdf

661-KOLNP-2006-PETITION UNDER RULE 137.pdf

661-kolnp-2006-reply to examination report.pdf


Patent Number 249601
Indian Patent Application Number 661/KOLNP/2006
PG Journal Number 44/2011
Publication Date 04-Nov-2011
Grant Date 31-Oct-2011
Date of Filing 21-Mar-2006
Name of Patentee ENGELHARD CORPORATION
Applicant Address 101, WOOD AVENUE ISELIN, NJ
Inventors:
# Inventor's Name Inventor's Address
1 REESINK, BERNARD, HENDRIK PATRIMONLUMWEG 6 3941 BT DOOM
2 VAN GASTEREN, NLCO NLEIHOEVE 6 3992 NS HOUTEN
PCT International Classification Number C07C 7/12
PCT International Application Number PCT/NL2004/000639
PCT International Filing date 2004-09-15
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 03077830.2 2003-08-23 EUROPEAN UNION